1. Field of the Invention
The invention relates to the field of power line communications, more particularly, to transceivers enabling such communications.
2. Prior Art
U.S. Pat. No. 4,918,690 describes a system for providing sensing, bidirectional communications, and control. Communications between a plurality of cells enables, for example, control for switching and the like. The present invention provides a transceiver for power line communications which may be used with the system described in U.S. Pat. No. 4,918,690.
A major problem with power line communications is background noise including impulse noise. This noise originates not only from the power source and distribution network, but also from the loads. The noise is not constant with respect to time, and moreover, it varies from place-to-place in a power distribution network. A theoretical analysis of impulse noise, particularly for twisted pair cabling, is described in "Errors-and-Erasures Coding to Combat Impulse Noise on Digital Subscriber Loops", IEEE Transactions on Communications, Vol. 38 No. 8, August, 1990, beginning at page 1145.
The present invention, as will be seen, employs snubbing or blanking to eradicate noise impulses. Snubbing or blanking has been used in connection with radio receivers, and such use is described in U.S. Pat. No. 4,124,819. Moreover, this technique has been used in power line communications as described in U.S. Pat. No. 5,210,518.